Acta Chimica Sinica ›› 1983, Vol. 41 ›› Issue (1): 90-94. Previous Articles     Next Articles

Original Articles

用氟钽酸根指示电位滴定钽的新方法

张国雄;王素芳;汪厚基   

  1. 中国科学院上海冶金研究所
  • 出版日期:1983-01-15 发布日期:1983-01-15

A new potentiometric titration method for the determination of tantalum using TaF6 ion selective indicator electrode

ZHANG GUOXIONG;WANG SUFANG;WANG HOUJI   

  • Online:1983-01-15 Published:1983-01-15

A new potentiometric titration method for the determination of tantalum in sulfuric acid and hydrofluoric acid media is described. EMF's were monitored with a double-junction reference electrode and a flurortantalate ion selective indicator electrode made in this laboratory previously. Five titrants have been evaluated for the precipitation titration. CPC, BDTAC and TPA yield the highest precision and largest potentiometric breaks, then rank CETAB and Hyamine 1622 in turn. CPC is considered to be the most satisfactory owing to the most sharp end-point break yielded when 10^-^4M of Ta is titrated with it. The concentration of H2SO4 suitable for the titration is 0.18 to 1.8M and that of HF is 0.23 to 1.7M. The method is suitable for Ta content in the range of 0.5 to 150 mg with a coefficient of variation of 0.15% (9 results) for 20 mg of Ta. HCl, H3PO4, tartaric acid and (NH4)2C2O4 as wellas a large amount of Fe^3^+, Ni^2^+, Cr^3^+, WO2^-^4, Zr^4^+, La^3^+, Al^3^+, MoO2^-^4 and Nb^5^+ do not interfere, while ClO^-^4, H2O2 and BF^-^4 must be avoided. The method has been found to be very useful for the determination of Ta in steels and crystalline lithium tantalate. The results obtained are in good agreement with those of comparable methods. This method is very simple and provides a fast determination process.

Key words: TANTALUM, POTENTIOMETRIC TITRATION, ION SELECTIVE ELECTRODE, LITHIUM COMPOUNDS, NICKEL BASE ALLOYS, TANTALATE P, TANTALATE P, FLUORO COMPLEX

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